Increased Urine Production Due to Leg Fluid Displacement Reduces Hours of Undisturbed Sleep

Low Urin Tract Symptoms. 2018 Sep;10(3):253-258. doi: 10.1111/luts.12176. Epub 2017 Jul 3.

Abstract

Objective: To investigate whether or not the leg fluid displacement observed when moving from the standing to recumbent position at bedtime reduces the hours of undisturbed sleep (HUS).

Methods: Men aged 50 years or older who were hospitalized for urological diseases were investigated. Body water evaluation was performed three times with a bioelectric impedance method: (i) 17:00, (ii) 30 min after (short-term), and (iii) waking up (long-term). A frequency volume chart was used to evaluate the status of nocturnal urine production, and the factors affecting HUS were investigated.

Results: A total of 50 patients (mean age: 68 years) were enrolled. Short-term changes in extracellular fluid (ECF in the legs showed a significant positive correlation with urine production per unit of time at the first nocturnal voiding (UFN/HUS) (r = 0.45, P = 0.01). In the comparison between patients who had <3 HUS vs. those who had ≥3 HUS, the <3 HUS group showed significantly greater short-term changes in leg fluid volume, night-time water intake (17:00-06:00), and UFN/HUS. Multivariate analysis to assess the risk factors for <3 HUS indicated UFN/HUS as a risk factor in the overall model, and short-term changes in leg ECF and night-time water intake as risk factors in the model that only considered factors before sleep.

Conclusions: Nocturnal leg fluid displacement may increase urine production leading up to first voiding after going to bed, and consequently, induce early awakening after falling asleep.

Keywords: bioelectric impedance analysis; body position changing; hours of undisturbed sleep; leg edema; nocturia.

MeSH terms

  • Aged
  • Body Water
  • Diuresis*
  • Drinking
  • Electric Impedance
  • Extracellular Fluid
  • Fluid Shifts*
  • Humans
  • Leg
  • Male
  • Middle Aged
  • Nocturia / etiology*
  • Posture / physiology*
  • Risk Factors
  • Sleep
  • Time Factors
  • Urination
  • Urine*